ENHANCED FLOCCULATION SEDIMENTATION PROCESS BY A JET MIXED SEPARATOR/

This paper deals with the performance of a jet mixed separator (JMS) w hich has a series of porous plates inserted in the channel perpendicul ar to a flow. The water passes through holes in the plates, thus creat ing jets which gently mix the water on itself. Simultaneous flocculati on of suspended particles and sedimentation of grown-flocs occur in th e JMS, because large-scale eddies in the vertical plane are almost abs ent in it. The JMS incorporated with inclined tube settlers was applie d to the rapid sand filtration system instead of the combination of me chanical flocculator and sedimentation basin. The turbidity of JMS eff luent was constantly below 1 TU at the hydraulic retention time of abo ut 1 hour. The JMS without inclined tube settlers was used as physico- chemical pretreatment process for the rotating biological contactors, The BOD and suspended solids concentration of JMS effluent were around 50 and 40 mg/L, respectively at the hydraulic retention time of 45 mi n. (C) 1998 Printed by Elsevier Science Ltd. All rights reserved